The invention relates to a method of frame synchronisation of a digital time-division multiplex (TDM) communication system wherein a frame comprises a sequence of N consecutive time slots at least one slot of which comprises at least one synchronisation bit and wherein M frames comprise one complete synchronisation pattern.
The invention further relates to an arrangement for performing the method.
Such a method or arrangement is used inter alia in "bit-interleaved T (time) D (division) M (Multiplex)" communication systems. With such systems data are transmitted in frames. A frame comprises a plurality of time slots N, each comprising a plurality of bits. Frames and time slots are transmitted serially. One of the time slots is utilized to transmit a synchronisation pattern therein. The time slot used for this purpose is often one bit long. At the receiving end each time slot must be identified in order to synchronize, for example, a demultiplexing arrangement or to supervise the existing synchronisation. A shift register having a capacity of N.times.M bits is usually used during the search for a synchronisation pattern of M-bits in frames composed of N time slots.